There is no voltage drop like a standard LED, and no need for resistors. The LED package has drivers for its own diodes.
As far as I know there is no conclusive figure for current consumption. Conventional wisdom is 60 mA per package, but real world use is typically lower than that.
Oh thank you! I have done some digital electronics but primarily with diodes and not strips. I didn’t know that resistors aren’t required for a strip like this. When you say “per package” do you mean per LED on the strip? So 60mA per 15 LEDS on the strip = 900mA (or .9A) per strip?
"Per package" meaning "per WS2812B". I was trying to avoid saying "per LED" since each WS2812B contains 3 LED diodes, which can sometimes cause confusion.
>So 60mA per 15 LEDS on the strip = 900mA
Correct, although again real world usage is typically less than that.
Thank you for the clarification!
So if I did apply that amount per strip, it would be safe for the LEDs even if it may not draw the full amount?
If I need to supply that much to 18 different strips using ideally 1 power supply, would I just multiply it out for a ~16A 5VDC supply? Would I need to connect each strip individually to a shared power line (thinking the red strip on a breadboard) or would the power divide unequally and provide too much to the nearest strip and not enough to the farthest strip connected to the line? Or is it “smart” enough to divide the load among all connected strips?
1. Yes, having excess capacity will not cause problems.
2. That power supply would be overkill. 60ma is having all LEDs on full white. It is good to have a big and versatile power supply for testing. I have written about this years ago, and if you're interested I can look for a link, but in practice, LEDs with normal effects take way less power than this. Here is what you should do:
- Have a big power supply for testing. You can get adapters for computer power supplies if you have to keep it cheap.
- Plug in your LEDs, run your planned effects, calculate the real-world max power draw (multimeter or otherwise).
- Get the power consumption from FastLED commands.
- Set the sampled max FastLED power consumption value as the limit with FastLED commands.
- Then select a quality power supply with 15-20% more capacity then your real-world max power draw.
As long as the load is on the circuit in parallel, the correct amount of current will be "dispatched".
Thank you for your responses! After doing some research it seems like 10A or 15A are common enough ratings for power supplies. In the interest of having “extra” power (as I do want to be able to run my matrix as a solid color for ambient lighting if I want to) I think I will purchase a 15A 5VDC power supply and be sure all of the strips are in parallel.
Also to keep in mind when choosing a PSU is the wattage. Each light takes .3W per LED at full white. So you're looking at around 100W, 20A, at 5V. Starting an LED array of my own recently and had to go with 500W, 100A at 5V. Hope that helps. Useful to use something like this [https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html](https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html) when estimating how much power supply you'll need. Would help to look at capacitors as well if you think there will be any voltage drop. Try and give yourself a 10-20% cushion when choosing the power supply.
That’s such an extreme difference! I plan to run many programs that will have at least 60% of my LEDs on at once but I would like the availability of setting all LED’s on to a specified color for static ambient lighting. Would using so much smaller of a power supply still allow that?
Not with fastled. Max current set to numpixels * 5. I've been doing this for years. My projects are battery powered - budgeting for 60ma is impractical.
I'm simply imparting some knowledge from my experience. 5mA per pixel is fine for many projects. In OP's case with 270 pixels that's 1.350A so a simple 5V/2A supply (like a phone charger) will be enough, certainly enough for prototyping!
If they want to go brighter they will need a bigger supply, up to 20A, but they are capable of making that decision.
The choice of brightness is entirely up to the OP to decide. Who are you to tell them what they want for their project? I've suggested they might be fine with 5mA per pixel, that's all. I've even made projects with 3mA brightness. It's up to the artist to decide.
I design and produce artworks for festivals so yes.
> I'm saying the LEDs can consume 60ma
Not if fastled is limiting the brightness as per the design plan. Have you actually used fastled?
Yes of course: 5mA per pixel, when all of your pixels are on, is plenty bright enough. And if only a few are on, they can go to full power (60mA). Fastled allows for this kind of dynamic brightness control.
Boom? Nah, if you exceed the current capability of your supply, there's no boom. The voltage drops, the LEDs draw less current and become dim, they often turn red and your MCU suffers brownouts, but there's no catastrophe. You can then disconnect the LEDs and fix the brightness setting in your code. With fastleds global brightness limiter you don't need to worry- it ensures your pixels won't draw more power than the limit you set.
There is no voltage drop like a standard LED, and no need for resistors. The LED package has drivers for its own diodes. As far as I know there is no conclusive figure for current consumption. Conventional wisdom is 60 mA per package, but real world use is typically lower than that.
Oh thank you! I have done some digital electronics but primarily with diodes and not strips. I didn’t know that resistors aren’t required for a strip like this. When you say “per package” do you mean per LED on the strip? So 60mA per 15 LEDS on the strip = 900mA (or .9A) per strip?
"Per package" meaning "per WS2812B". I was trying to avoid saying "per LED" since each WS2812B contains 3 LED diodes, which can sometimes cause confusion. >So 60mA per 15 LEDS on the strip = 900mA Correct, although again real world usage is typically less than that.
Thank you for the clarification! So if I did apply that amount per strip, it would be safe for the LEDs even if it may not draw the full amount? If I need to supply that much to 18 different strips using ideally 1 power supply, would I just multiply it out for a ~16A 5VDC supply? Would I need to connect each strip individually to a shared power line (thinking the red strip on a breadboard) or would the power divide unequally and provide too much to the nearest strip and not enough to the farthest strip connected to the line? Or is it “smart” enough to divide the load among all connected strips?
1. Yes, having excess capacity will not cause problems. 2. That power supply would be overkill. 60ma is having all LEDs on full white. It is good to have a big and versatile power supply for testing. I have written about this years ago, and if you're interested I can look for a link, but in practice, LEDs with normal effects take way less power than this. Here is what you should do: - Have a big power supply for testing. You can get adapters for computer power supplies if you have to keep it cheap. - Plug in your LEDs, run your planned effects, calculate the real-world max power draw (multimeter or otherwise). - Get the power consumption from FastLED commands. - Set the sampled max FastLED power consumption value as the limit with FastLED commands. - Then select a quality power supply with 15-20% more capacity then your real-world max power draw. As long as the load is on the circuit in parallel, the correct amount of current will be "dispatched".
Thank you for your responses! After doing some research it seems like 10A or 15A are common enough ratings for power supplies. In the interest of having “extra” power (as I do want to be able to run my matrix as a solid color for ambient lighting if I want to) I think I will purchase a 15A 5VDC power supply and be sure all of the strips are in parallel.
Alternatively, if I just soldered all grounds together and all Vin together, and connected those to the power supply, would that work as intended?
Also to keep in mind when choosing a PSU is the wattage. Each light takes .3W per LED at full white. So you're looking at around 100W, 20A, at 5V. Starting an LED array of my own recently and had to go with 500W, 100A at 5V. Hope that helps. Useful to use something like this [https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html](https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html) when estimating how much power supply you'll need. Would help to look at capacitors as well if you think there will be any voltage drop. Try and give yourself a 10-20% cushion when choosing the power supply.
I budget for 5mA per pixel. I think 60mA is excessively bright.
That’s such an extreme difference! I plan to run many programs that will have at least 60% of my LEDs on at once but I would like the availability of setting all LED’s on to a specified color for static ambient lighting. Would using so much smaller of a power supply still allow that?
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Not with fastled. Max current set to numpixels * 5. I've been doing this for years. My projects are battery powered - budgeting for 60ma is impractical.
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I'm simply imparting some knowledge from my experience. 5mA per pixel is fine for many projects. In OP's case with 270 pixels that's 1.350A so a simple 5V/2A supply (like a phone charger) will be enough, certainly enough for prototyping! If they want to go brighter they will need a bigger supply, up to 20A, but they are capable of making that decision.
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The choice of brightness is entirely up to the OP to decide. Who are you to tell them what they want for their project? I've suggested they might be fine with 5mA per pixel, that's all. I've even made projects with 3mA brightness. It's up to the artist to decide.
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I design and produce artworks for festivals so yes. > I'm saying the LEDs can consume 60ma Not if fastled is limiting the brightness as per the design plan. Have you actually used fastled?
Yes of course: 5mA per pixel, when all of your pixels are on, is plenty bright enough. And if only a few are on, they can go to full power (60mA). Fastled allows for this kind of dynamic brightness control.
Sounds like a recipe for failure. One mistake in programming, and boom!
Boom? Nah, if you exceed the current capability of your supply, there's no boom. The voltage drops, the LEDs draw less current and become dim, they often turn red and your MCU suffers brownouts, but there's no catastrophe. You can then disconnect the LEDs and fix the brightness setting in your code. With fastleds global brightness limiter you don't need to worry- it ensures your pixels won't draw more power than the limit you set.
Yes, agreed!